Stainless Steel Screw Quality Inspection: 6 Methods We Rely On

Stainless steel screws are chosen for one reason above all: they do not rust. But not all stainless steel is created equal, and quality control decides whether a screw serves for decades or fails within months.

1. Raw material verification

Every batch starts with verified material certificates confirming the grade - SS304, SS316 or other - with correct chromium, nickel and molybdenum content. We source only from certified steel mills.

2. Dimensional inspection

Using projectors and precision gauges, we verify head dimensions, thread pitch and diameter against drawings. Tolerances are held tightly to ensure assembly compatibility.

3. Salt spray testing

Corrosion resistance is proven, not assumed. Samples from each batch are tested in salt spray chambers according to GB12335, with resistance up to 1,200+ hours for premium finishes.

4. Hardness testing

Hardness is measured to ensure the screw meets specification and that heat treatment (where applied) is consistent across the batch.

5. Thread go/no-go gauge inspection

Thread accuracy is verified with go/no-go gauges - a simple but rigorous check that guarantees screws mate cleanly with nuts and threaded holes.

6. 100% optical sorting

Finally, fully-automatic optical sorting machines inspect every single piece for dimensional, surface and thread defects. This is how we achieve a 99.9%+ qualified rate on every shipment.

Need rust-proof fasteners that last? Explore our stainless steel screws or contact our team.